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At least 1,045 records · Page 58

Thermal Protection Materials and Systems: Past, Present, and Future

Thermal protection materials and systems (TPS) protect vehicles from the heat generated when entering a planetary atmosphere. NASA has developed many TPS systems over the years for vehicle ranging from planetary probes to crewed vehicles. The goal for all TPS is efficient and reliable performance. Efficient means using the right material for the environment and minimizing the mass of the heat shield without compromising safety. Efficiency is critical if the payload such as science experiments is to be maximized on a particular vehicle. Reliable means that we understand and can predict performance of the material. Although much characterization and testing of materials is performed to qualify and certify them for flight, it is not possible to completely recreate the reentry conditions in test facilities, and flight-testing

Johnson, Sylvia M.↗

Space Launch System Base Heating Test: Sub-Scale Rocket Engine/Motor Design, Development and Performance Analysis

The Space Launch System (SLS) base heating test is broken down into two test programs: (1) Pathfinder and (2) Main Test. The Pathfinder Test Program focuses on the design, development, hot-fire test and performance analyses of the 2% sub-scale SLS core-stage and booster element propulsion systems. The core-stage propulsion system is composed of four gaseous oxygen/hydrogen RS-25D model engines and the booster element is composed of two aluminum-based model solid rocket motors (SRMs). The first section of the paper discusses the motivation and test facility specifications for the test program. The second section briefly investigates the internal flow path of the design. The third section briefly shows the performance of the model RS-25D engines and SRMs for the conducted short duration hot-fire tests. Good agreement is observed based on design prediction analysis and test data. This program is a challenging research and development effort that has not been attempted in 40+ years for a NASA vehicle.

Mehta, Manish↗

System Level Aerothermal Testing for the Adaptive Deployable Entry and Placement Technology (ADEPT)

The Adaptive Deployable Entry and Placement Technology (ADEPT), a mechanically deployable entry vehicle technology, has been under development at NASA since 2011. As part of the technical maturation of ADEPT, designs capable of delivering small payloads (10 kg) are being considered to rapidly mature sub 1 m deployed diameter designs. The unique capability of ADEPT for small payloads comes from its ability to stow within a slender volume and deploy to achieve a mass efficient drag surface with a high heat rate capability. The low ballistic coefficient results in entry heating and mechanical loads that can be met by a revolutionary three-dimensionally woven carbon fabric supported by a deployable skeleton structure. This carbon fabric has test proven capability as both primary structure and payload thermal protection system. In order to rapidly advance ADEPTs technical maturation, the project is developing test methods that enable thermostructural design requirement verification of ADEPT designs at the system level using ground test facilities. Results from these tests are also relevant to larger class missions and help us define areas of focused component level testing in order to mature material and thermal response design codes. The ability to ground test sub 1 m diameter ADEPT configurations at or near full-scale provides significant value to the rapid maturation of this class of deployable entry vehicles. This paper will summarize arc jet test results, highlight design challenges, provide a summary of lessons learned and discuss future test approaches based upon this methodology.

Hypersonic↗

Aircraft Fault Detection Using Real-Time Frequency Response Estimation

A real-time method for estimating time-varying aircraft frequency responses from input and output measurements was demonstrated. The Bat-4 subscale airplane was used with NASA Langley Research Center's AirSTAR unmanned aerial flight test facility to conduct flight tests and collect data for dynamic modeling. Orthogonal phase-optimized multisine inputs, summed with pilot stick and pedal inputs, were used to excite the responses. The aircraft was tested in its normal configuration and with emulated failures, which included a stuck left ruddervator and an increased command path latency. No prior knowledge of a dynamic model was used or available for the estimation. The longitudinal short period dynamics were investigated in this work. Time-varying frequency responses and stability margins were tracked well using a 20 second sliding window of data, as compared to a post-flight analysis using output error parameter estimation and a low-order equivalent system model. This method could be used in a real-time fault detection system, or for other applications of dynamic modeling such as real-time verification of stability margins during envelope expansion tests.

Grauer, Jared A.↗

Heatshield for Extreme Entry Environment Technology (HEEET) Development Status

The Heat shield for Extreme Entry Environment Technology (HEEET) Project is a NASA STMD and SMD co-funded effort. The goal is to develop and mission infuse a new ablative Thermal Protection System that can withstand extreme entry. It is targeted to support NASAs high priority missions, as defined in the latest decadal survey, to destinations such as Venus and Saturn in-situ robotic science missions. Entry into these planetary atmospheres results in extreme heating. The entry peak heat-flux and associated pressure are estimated to be between one and two orders of magnitude higher than those experienced by Mars Science Laboratory or Lunar return missions. In the recent New Frontiers community announcement NASA has indicated that it is considering providing an increase to the PI managed mission cost (PIMMC) for investigations utilizing the Heat Shield for Extreme Entry Environment Technology (HEEET) and in addition, NASA is considering limiting the risk assessment to only their accommodation on the spacecraft and the mission environment. The HEEET ablative TPS utilizes 3D weaving technology to manufacture a dual layer material architecture. The 3-D weaving allows for flat panels to be woven. The dual layer consists of a top layer designed to withstand the extreme external environment while the inner or insulating layer by design, is designed to achieve low thermal conductivity, and it keeps the heat from conducting towards the structure underneath. Both arc jet testing combined with material properties have been used to develop thermal response models that allows for comparison of performance with heritage carbon phenolic. A 50 mass efficiency is achieved by the dual layer construct compared to carbon phenolic for a broad range of missions both to Saturn and Venus. The 3-D woven flat preforms are molded to achieve the shape as they are compliant and then resin infusion with curing forms a rigid panels. These panels are then bonded on to the aeroshell structure. Gaps exist between the panels and these gaps have to be filled with seams. The seam material then has to be bonded on to adjacent panels and also to the structure. The heat-shield assembly is shown in Figure 1. One of the significant challenges we have overcome recently is the design, development and testing of the seam. HEEET material development and the seam concept development have utilized some of the unique test capabilities available in the US. The various test facilities utilized in thermal testing along with the entry environment for Saturn and Venus missions are shown in Figure 2. The HEEET project is currently in its 3rd year of a four-year development. Figure 3 illustrates the key accomplishments to date and the challenges yet to be overcome before the technology is ready for mission infusion. This proposed presentation will cover both progress that has been made in the HEEET project and also the challenges to be overcome that is highlighted in Figure 3. Objective of the HEEET project is to mature the system in time to support the next New Frontiers opportunity and we believe we are well along the way to mission infuse HEEET.

Thermal Protection System↗

Heat-shield for Extreme Entry Environment Technology (HEEET) Development Status

The Heat shield for Extreme Entry Environment Technology (HEEET) Project is a NASA STMD and SMD co-funded effort. The goal is to develop and mission infuse a new ablative Thermal Protection System that can withstand extreme entry. It is targeted to support NASA's high priority missions, as defined in the latest decadal survey, to destinations such as Venus and Saturn in-situ robotic science missions. Entry into these planetary atmospheres results in extreme heating. The entry peak heat-flux and associated pressure are estimated to be between one and two orders of magnitude higher than those experienced by Mars Science Laboratory or Lunar return missions. In the recent New Frontiers community announcement NASA has indicated that it is considering providing an increase to the PI managed mission cost (PIMMC) for investigations utilizing the Heat Shield for Extreme Entry Environment Technology (HEEET) and in addition, NASA is considering limiting the risk assessment to only their accommodation on the spacecraft and the mission environment. The HEEET ablative TPS utilizes 3D weaving technology to manufacture a dual layer material architecture. The 3-D weaving allows for flat panels to be woven. The dual layer consists of a top layer designed to withstand the extreme external environment while the inner or insulating layer by design, is designed to achieve low thermal conductivity, and it keeps the heat from conducting towards the structure underneath. Both arc jet testing combined with material properties have been used to develop thermal response models that allows for comparison of performance with heritage carbon phenolic. A 50% mass efficiency is achieved by the dual layer construct compared to carbon phenolic for a broad range of missions both to Saturn and Venus. The 3-D woven flat preforms are molded to achieve the shape as they are compliant and then resin infusion with curing forms a rigid panels. These panels are then bonded on to the aeroshell structure. Gaps exist between the panels and these gaps have to be filled with seams. The seam material then has to be bonded on to adjacent panels and also to the structure. The heat-shield assembly is shown in Figure 1. One of the significant challenges we have overcome recently is the design, development and testing of the seam. HEEET material development and the seam concept development have utilized some of the unique test capabilities available in the US. The various test facilities utilized in thermal testing along with the entry environment for Saturn and Venus missions are shown in Figure 2. The HEEET project is currently in it's 3rd year of a four-year development. Figure 3 illustrates the key accomplishments to-date and the challenges yet to be overcome before the technology is ready for mission infusion. This proposed presentation will cover both progress that has been made in the HEEET project and also the challenges to be overcome that is highlighted in Figure 3. Objective of the HEEET project is to mature the system in time to support the next New Frontiers opportunity and we believe we are well along the way to mission infuse HEEET.

TPS↗

Overview of Power Quality and Integrated Testing at JSC

This presentation describes the basic philosophy behind integrated testing and partially integrated testing. It lists some well known errors in space systems that were or could have been caught during integrated testing. Two examples of integrated testing at the Johnson Space Center (JSC) are mentioned, and then an overview of two test facilities that do power testing (partially integrated testing) at JSC are presented, with information on the capabilities of each. Finally a list of three projects that has problems caught during power quality or Electromagnetic Interference (EMI) testing is presented.

Davies, Francis↗

Test and Analysis of Buckling-Critical Stiffened Metallic Launch Vehicle Cylinders

A summary of a NASA design analysis and test program on the buckling of large-scale, integrally-stiffened metallic cylinders is presented. The test article designs were developed based on proposed NASA launch vehicle cylinder designs and span a significant portion of the design space. Various loading conditions were applied to the cylinders and include different combinations of axial compression, bending, and internal pressure loads that simulate typical launch vehicle loading scenarios. The data gathered from this test program is being used to develop and validate new analysis-based knockdown factors and design guidelines for these stiffened metallic cylinders. In this paper, the test article designs and fabrication methods are described along with the test facilities and instrumentation. Selected test and finite element analysis results are presented and compared and are used to illustrate the typical response characteristics of the stiffened metallic cylinders considered. Overall, good qualitative agreement is found, however, several discrepancies in the results were identified across several of the tests. The discrepancies were investigated thoroughly and can be attributed to variations in the as-built skin and stiffener geometry, variations in the measured geometric imperfection, and modeling assumptions associated with the boundary conditions, and loading imperfections. Based on these findings, several refinements were made to the finite element models which significantly improved the correlation between the test and analysis results. These modeling refinements are described and the updated analysis results are presented.

Hilburger, Mark W.↗

Hypervelocity Impact Performance of 3D Printed Aluminum Panels

With the continued development of additive manufacturing methods, control over the shape of ligaments, cell regularity, and macroscopic shape can all be easily tuned. This capability allows for tailoring of component architecture and promotes potential mass savings in a space vehicle structure. Additionally, it allows one the flexibility of combining structural elements such as MMOD protection and vehicle stiffness for launch loads for an overall mass reduction. At NASA JSC this technology is being explored in many different ways with the goal being a multifunctional structural component. For this study, four different types of aluminum panels have been 3D printed for testing, three being of a body centric cubic (BCC) lattice structure core and one being kelvin cell structure core. All samples have a 5.33 cm (0.05”) nominally thick aluminum face sheet printed on the front and back side of each panel, with all core materials having a 5.08 cm (2.0”) nominal thickness (see Table 1 for test sample summary and Figures 1 – 2 for sample illustrations). These tests will evaluate the performance of 3D printed aluminum panels under hypervelocity impact (HVI) conditions. The hypervelocity impact tests are being conducted at the JSC White Sands Test Facility (WSTF) Remote Hypervelocity Test Laboratory (RHTL), located in Las Cruces, New Mexico. All tests will be conducted with a 3.4mm Al 2017-T4 sphere at 6.8 km/s impacting at 0° to surface normal (i.e., impacting with no obliquity). Each sample will be trapped between two metal frames, with gasket material residing between the sample and frame, which will be the shipping and testing configuration for all tests. There will be an Al 2017-T4 witness plate staged 5.08 cm (2.0”) from each sample to capture signature of debris, if the rear face sheet of the sample were to perforate from the HVI test event.

Davis, B. A.↗

Update: Evaluation of Additively Manufactured Metals for Use in Oxygen Systems

Evaluation of Additively Manufactured Metals for Use in Oxygen Systems. Oxygen Compatibility: Additive Manufacturing (AM) is currently and will continue to be, used in oxygen systems; Compatibility studies are a necessity; Risks if not pursued - Equipment Damage, Loss of Mission, Loss of Life; NASA Centers of Excellence leading efforts -White Sands Test Facility (WSTF), Oxygen Compatibility Testing -Marshall Space Flight Center (MSFC), Additive Manufacturing -Glenn Research Center, Metals characterization -NASA Engineering Safety Center (NESC), Statistical Design of Experiments.

Tylka, Jonathan↗

A Ground Testing Program to Verify Lunar Dust-Tolerant Hardware for the Artemis Mission

In preparation for NASA’s Artemis Mission that will return humans to the surface of moon by 2024, an extensive test campaign will be undertaken to understand the effects of lunar dust contamination on equipment. Historically, early Apollo astronauts were affected by lunar dust that entered the cabin after their extravehicular activities, and subsequent missions had various cleaning protocols to reduce the impact of the contamination. The longest stays on the lunar surface were Apollo 15, 16, and 17 (just over three days), so equipment and suits were required to operate reliably for a relatively short duration. The ultimate goal of Artemis is a sustained human presence on the lunar surface, beginning with Artemis 3 which targets a six-and-a-half day surface deployment. This requires the design and testing of dust-tolerant infrastructure. Ground testing with aerosolized lunar dust simulants in a specialized chamber is an inexpensive way to verify the performance of equipment. Chambers equipped with various powder dispersers and analysis instrumentation can explore a variety of realistic scenarios relevant to lunar surface missions, from the interaction of dust with sensitive surfaces such as solar panels, textiles, radiators, and scientific equipment, to the effects of dust as it intrudes into habitable areas. These experiments require careful consideration of the expected mass concentrations, aerosolization methods, and transport properties of dust. Instruments that use light-scattering techniques to measure mass concentrations require calibration against lunar simulants for improved accuracy, and different simulants may have different calibration factors. Test facilities, laboratory setup and test methods for aerosolizing lunar simulant will be described along with relevant aerosol instruments and calibration efforts.

Benjamin J Sumlin↗

HFE 7100 Compatibility with Orbiter Materials

Chlorofluorocarbon (CFC) 113 is currently specified as the precision cleaning and verification fluid for orbiter materials. The production ban of CFC 113, an ozone-depleting chlorofluorocarbon, has resulted in a search for a replacement cleaning fluid. Recently, the 3M Company announced the manufacture of a new class of cleaning fluids, hydrofluoroethers. The first in this class of cleaning fluids is HFE 7100, perfluorobutyl methyl ether. This cleaning fluid has been submitted for consideration as a replacement for CFC 113. One of the requirements of the certification process for a replacement cleaning fluid is compatibility testing. The Johnson Space Center (JSC) Materials and Manufacturing Division has requested that NASA JSC White Sands Test Facility perform the compatibility testing with HFE 7100 on selected orbiter materials. Most of the materials selected for testing were previously evaluated for compatibility with CFC 113. Some of the materials are new additions to the orbiter or were not available when the compatibility testing was performed with CFC 113. These materials were evaluated with both cleaning fluids and the results were used to compare the response to the cleaning fluid and to satisfy the certification process requirements. It was found that HFE 7100 is generally compatible with the materials tested.

Chlorofluorocarbon↗

A New Test Methodology for Evaluating Fire Risk Due to Electrical Faults in Oxygen-Enriched Environments

This paper discusses a new test methodology for assessing the safe use of materials found in spacecraft that may be exposed to electrical faults, as performed at the NASA White Sands Test Facility. “Wire-break” testing, modeled after the Cleveland Open Cup method, identifies the conditions under which pyrolyzed material transitions from a brief flash to a propagating flame. The approach focuses on fuel mass liberated through pyrolysis, mixed with oxygen, and ignited by a piloted ignition (spark due to fusion of wire) to achieve flame propagation with the least energy. The test approach attempts to find energy density thresholds derived using I²t values from current-induced heating of various test materials and wire characteristics. The application of the data provides a useful approach to mitigating fire risks in space systems by correlating threshold data to real-world designs and scaling factors, including oxygen pressure, wire diameter, heat sinking, and contained smoke volume. Several case studies, including Apollo missions and hypothetical scenarios, illustrate practical applications of these thresholds to enhance fire safety design considerations in space environments.

methodology↗

Improvement of Odor Control for the UWMS Hard-Sided Fecal Canister and the Alternate Fecal Canister

On longer range exploration missions, the mass and volume of critical hardware and consumables required to support crew will pose a big stowage challenge. This includes the hardware for the collection and storage of human metabolic solid waste. The amount of stowage needed for this hardware both before (empty) and after (full) use will be a significant burden on the overall spacecraft habitable volume, layout, and design. To help with this challenge, the National Aeronautics and Space Administration (NASA) Mars Campaign Office (MCO) Logistics Reduction (LR) Portfolio has developed a collapsible canister for the collection and containment of fecal deposits. The Alternate Fecal Canister (AFC) is a collapsible alternative to the exploration toilet Hard-sided Fecal Canister (HFC). The AFC in its empty state has a volumetric benefit to smaller vehicles on longer missions. The current designs for HFC and AFC were tested with human fecal material for odor containment at White Sands Test Facility (WSTF) where the tests on both were unsuccessful. The source of the lack of containment was isolated to a gasket used on both HFC and AFC. The gasket used was found to be open cell in design. This paper provides a summary of the materials selection and testing process to identify a replacement gasket material with the intention to replace the gaskets on both existing units as well as incorporate it into the designs going forward for future builds for exploration. Details will be provided on the design of the canisters interface with the odor bacteria lid which led to the selection of the thickness of the desired replacement. Finally, the paper will provide an update on the testing in advance of a return to WSTF for final testing and detail plans to complete testing and perform a demonstration on ISS with UWMS.

ECLSS↗

Improvement of Odor Control for the UWMS Hard-Sided Fecal Canister and the Alternate Fecal Canister

On longer range exploration missions, the mass and volume of critical hardware and consumables required to support crew will pose a big stowage challenge. This includes the hardware for the collection and storage of human metabolic solid waste. The amount of stowage needed for this hardware both before (empty) and after (full) use will be a significant burden on the overall spacecraft habitable volume, layout, and design. To help with this challenge, the National Aeronautics and Space Administration (NASA) Mars Campaign Office (MCO) Logistics Reduction (LR) Portfolio has developed a collapsible canister for the collection and containment of fecal deposits. The Alternate Fecal Canister (AFC) is a collapsible alternative to the exploration toilet Hard-sided Fecal Canister (HFC). The AFC in its empty state has a volumetric benefit to smaller vehicles on longer missions. The current designs for HFC and AFC were tested with human fecal material for odor containment at White Sands Test Facility (WSTF) where the tests on both were unsuccessful. The source of the lack of containment was isolated to a gasket used on both HFC and AFC. The gasket used was found to be open cell in design. This paper provides a summary of the materials selection and testing process to identify a replacement gasket material with the intention to replace the gaskets on both existing units as well as incorporate it into the designs going forward for future builds for exploration. Details will be provided on the design of the canisters interface with the odor bacteria lid which led to the selection of the thickness of the desired replacement. Finally, the paper will provide an update on the testing in advance of a return to WSTF for final testing and detail plans to complete testing and perform a demonstration on ISS with UWMS.

Toilet↗